Uxcell a14061100ux0040 NO Wired Door Window Sensor Magnetic Switch Home Alarm System 15-25mm (Pack of 10) Product name: door magnetic reed switch; model: ho-03c; contact type: nc(normally close) Contact capacity: 0.5A; voltage: dc 100V; rated power: 10W Actuation distance: 15-25mm; each size(approx): 17.5 x 11 mm/ 0.7" x 0.43"(H*d); cable length(each): 26Cm/ 10.2"